Note how I’m applying my terminology, however. I’m staying away from calling it a “census” because, while accurate in the strict sense, this document isn’t the sort of thing we family researchers can spend hours obsessing over on Ancestry.com. Naturally the word “census” may sneak into some headlines, getting people all hot and bothered.

Easy, tiger. Although very interesting, this doesn’t appear to contain information on specific names and their domiciles. It’s a tally of U.S. populations, state by state, drawn from state enumerations taken between 1781 and 1786. For some states, the tallies are broken down by age and race, but other states simply provided a total tally.

The information was found among papers belonging to John Kean, a member of a family still very much active in New Jersey politics today — former governor and 9/11 Commission member Thomas Kean is one example. (In New Jersey, Keans and Livingstons and Frelinghuysens are like the Appalachian Mountains of public life: they’ve just always been there.)

Descendants of the Kean and Livingston families donated a trove of papers to Kean University (no relation? What do you think?). And Kean University archivists have been slowly combing through what they describe as 200 years of American history, which is probably a good thing — researchers say all sorts of goodies keep turning up in odd places.

The population count, for example, was scribbled in a ledger that John Kean originally used for keeping accounts. Being a thrifty sort, he turned it over and used the reverse pages for taking notes when he was elected to the Continental Congress in 1785.

The count said that 2.2 million whites and Indians were living in the U.S.A., along with 567,000 blacks. Virginia had the biggest population, with 530,000 residents, more than half of them black. (New Jersey, by contrast, had about 159,000 residents.)

While it probably won’t set off any lightning bolts for individual genealogy research, the discovery does provide a nice snapshot of the United States at the dawn of its existence.